No structural gear for 2 of the 3 of us. I had civilian gear on other than my EMS jacket which despite not being "proper outdoor gear" is insanly warm. Thankfully I had also layered a merino wool base layer and my RAB thinsulate-y puffer jacket under that, REI expedition gloves and two layers of hats. One of my colleagues did not do so well, and was really inadequately dressed given that we had to strip down a bit to keep her warm. The 3rd person on the team wore his structural jacket and wildland helmet.

The UTV1 crew had their structural jackets on, but otherwise civilian.

Y'all are experts here. May I ask, are those mylar blankets really a thing ? Do they work ?

Hi, I don’t have their expertise but I backpack and camp a lot, including in some pretty hostile environments. I keep a pack of 12 in my trunk for emergencies. The answer is yes, they’re a thing and they work. They’re super lightweight. However, I wouldn’t want to use one unless I had to. They keep you warm by trapping all of the moisture and humidity from your body inside. This means you’ll feel clammy and sweaty if you use one for long. This is why they’re called “emergency blankets”.

But they trap the body heat too, yes ?

Yes